The present invention relates to a device which is arranged in a stapler for locking a member displaceable along a bar in an optional displacement position, said member carrying a catch for the object to be stapled, and said device having a locking means connected to the displaceable member and displaceable together with the same, said locking means having a through hole, through which the bar extends and which is designed such that the locking means is tiltable along the bar between a front position, pinch position, in which the locking means portion defining the hole engages the bar and pinches the locking means thereto, and a rear position, free position, in which this hole defining portion goes clear of the bar, the locking means being spring-biased towards its pinch position.
A device of this type is known from WO 88/08932. In this prior-art device, the locking means consists of a washer which is non-rotatably connected to the bar. The bar is turnable back and forth in order to tilt the washer between its free position and its pinch position. The bar extends along the stapler and protrudes at the front thereof. An operating knob is fixed to the projecting front end of the bar. A torsion spring is arranged to bias the bar towards a turning position, in which the bar keeps the washer in its pinched position. The known device has a relatively complicated construction in that it consists of many components. However, it has above all the drawback that when operating the device the user must use both hands, viz. his one hand to seize the operating knob and turn the bar and his other hand to displace the displaceable member along the bar.
The object of the present invention therefore is to provide a locking device, whose construction is simple and which is operable by means of one hand only.
According to the present invention, this object is achieved by a device which is of the type described by way of introduction and characterized in that the device further has an operating handle which is mounted on the displaceable member and operable from the outside of the stapler, said operating handle being displaceable to a limited extent in relation to the displaceable member essentially parallel with the bar in order to move, in connection with forwards displacement, the displaceable member and, thus, the catch forwards along the bar and in order to be engaged, in connection with backwards displacement, with the locking means and tilt the same towards its free position and thereby move the displaceable member and, thus, the catch backwards along the bar.
The locking means preferably is a blade shaped arm, which is tiltably fixed in the displaceable member at its one end and is arranged to cooperate with the operating handle at its other end.
In a preferred embodiment, the hole extends through the arm perpendicular to the plane sides thereof, and the arm extends essentially perpendicular to the bar in its free position.
The arm advantageously consists of a piece of sheet metal.
The operating handle is preferably displaceable relative to the displaceable member between a front end position, in which it engages the displaceable member in order to displace this forwards, and a rear end position, in which it retains the locking means in its free position.
The operating handle is suitably spring-biased towards its front position.